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CryoSat. Credit: ESA/P. Carril

On Monday 9 July, 2018, engineers based at the European Space Operations Centre (ESOC) in Germany made the decision to alter the path of the CryoSat satellite, preventing a potentially fatal collision between it and an ‘unknown object’. For the second time this year the risk of collision was deemed high enough to give the satellite instructions to get out of the way.

CryoSat is ESA’s mission dedicated to measuring the thickness of polar sea ice and monitoring changes in the ice sheets blanketing Greenland and Antarctica. Flying at an altitude of just over 700 km and travelling from pole to pole, Cryosat keeps us informed about an often cited ‘early casualty’ of global warming, Earth’s ice.

The first warning of trouble came about a week before the event from the Joint Space Operations Center (JSpOC) in the US, informing ESA’s Space Debris Office that a potential collision was on the horizon.

Time of close approach: Monday 9 July, 04:24 UTC.

3D collision plot. Credit: Spacecraft Conjunction Assessment and Risk Front-end (SCARF)

“We received the first CDM (Conjunction Data Message) from JSpOC on 2 July 2018 at 08:02 UTC. At this point the chance of collision was still below our threshold of 1 in 10 000. By 5 July 2018, 23:00 UTC, the probability had climbed above the threshold and we informed the mission the next morning.” describes Vitali Braun, Space Debris Engineer at ESA’s Space Debris Office.

“It is a somewhat different feeling than usual work, but there’s only a small amount of stress or concern. The teams involved know exactly what to do and everyone is very professional.”

CryoSat operations team waiting for updates from the satellite at the Earth Observation Control Room at ESOC

So the warning was passed from the Space Debris office to the team operating CryoSat at the Earth Observation Mission Control Room.

Giuseppe Albini, CryoSat Spacecraft Operations Engineer recounts: “The object was approaching from behind and below CryoSat, and even though its orbit is monitored and tracked, its origin is unknown. We had one lunchtime meeting with the Space Debris Office, Flight Dynamics, the Flight Control Team and the Mission Manager, Tommaso Parrinello. Considering the collision probability exceeded 1/10000, we decided to prepare the manoeuvre, and as this was happening over the weekend, cancel our plans!”

Getting CryoSat to safety

On Sunday the commands were sent to CryoSat, on Monday, 50 minutes before the potential collision, its thrusters fired, and because of the swift action of many experienced and dedicated teams the chance of collision dropped from 1 in 10 000 to 1 in 1 000 000.

By firing its thrusters CryoSat increased its speed, and in so doing increased its ‘orbital energy’, pushing it into a higher orbit around the Earth. Instead of a distance of 14-metres between the two objects at their closest point, CryoSat passed more than 120-metres above the unknown object, or ‘chaser’.

Chasers might be operational satellites, dead satellites, spent rocket parts, mission-related debris e.g. lens covers, payload adapters, and the most common source, explosion and collision fragments.

Back to work

CryoSat. Credit: ESA/AOES

After it was confirmed that CryoSat had successfully avoided collision, the operations team began preparations to get it back into an orbit that would allow it to continue its vital work.

“The collision avoidance manoeuvre performed early on Monday raised the orbit of CryoSat outside the optimal altitude. We are currently preparing the commands that will implement a second manoeuvre, ensuring CryoSat is able to satisfy its scientific mission in the weeks to come,” explained Elia Maestroni, CryoSat-2 Spacecraft Operations Manager.

With these commands CryoSat again fired its thrusters, but this time in the opposite direction, slowing it down by 3.043 cm/s and so lowering its orbit.

By Thursday, CryoSat was back at work.

The problem of junk

Artist’s impression of space debris around Earth. Credit: ESA/ID&Sense/ONiRiXEL, CC BY-SA 3.0 IGO

None of this would have been possible without the dedication and experience of the teams involved, but an event like this still comes at some cost. Every time CryoSat fires its thrusters it uses some of its fuel, ultimately shortening the length of its mission.

This is CryoSat’s second Collision Avoidance Manoeuvre of 2018 and the 14th since it launched in 2000, and according to Vitali Braun, events like this are becoming more common:

“about 50% of all alerts and Collision Avoidance Manoeuvres at ESOC are due to fragments left over from two particular events: the anti-satellite test conducted by the Chinese military in 2007, which destroyed the former weather satellite Fengyun-1C and left a huge debris cloud behind, and the collision of two intact spacecraft, Iridium-33 and Cosmos-2251, in 2009. One could say that we have doubled the amount of chaser objects since 2007 and thus also the frequency of manoeuvres like this. This only applies however to our satellites in Low Earth Orbit, like the Sentinels, CryoSat and Swarm.”

By the end of 2017, 19 894 bits of space junk were known to be circling our planet with a combined mass of 8000 tones, and unfortunately these numbers are increasing.The goal now is to remove debris from space, at the same time as preventing any more getting there in the first place. ESA has taken a leading role in this mission, with the creation of the Space Debris Office, which comes under its Space Situational Awareness Programme, and the Clean Space initiative.

For more information on the problem of debris, check out ESA’s 2017 report on space junk.

Space debris GIF. Credit: ESA, CC BY-SA 3.0 IGO

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ESA | Rocket Science by Daniel - 2w ago

Salma Fahmy, team member on the Solar Orbiter Project Office at ESTEC Credit: ESA/D. Lakey

ESA’s Solar Orbiter team have been busy for the last few months preparing for the first ‘Spacecraft Validation Test’ – referred to in engineering-speak as ‘SVT-0’ – which is the first opportunity the mission control team to establish a data link to the actual flight hardware and send commands to the spacecraft.

The mission controllers are working at ESA’s ESOC control centre in Darmstadt this week, joined by representatives from the mission’s two instrument teams, the ESA Project Team based at ESTEC in the Netherlands and the AirbusDS-UK industrial team. The spacecraft itself is located in Stevenage, UK.

Jose-Luis Pellon-Bailon & Matthias Eiblmaier Credit: ESA/D. Lakey

Yesterday and today, the team will validate flight control procedures and the database that describes the commands and telemetry of the spacecraft. It’s a lot of work but at the end of it, a real milestone will have been passed.

Spacecraft Operations Engineer Daniel Lakey explains, “This is the culmination of months of work by us, our colleagues across ESA and, of course, the teams at AirbusDS-UK, who are leading the build of the spacecraft and are supporting these test connections from the cleanroom in Stevenage.”

“We have a list of over 250 procedures that we will methodically go through, to ensure they are ready for flight. This first contact with the real spacecraft is an exciting step after having spent years working on paper!”

More tests are planned over the coming months, and next year.

#Solo

#ESOC

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An aerial view of ESTEC from this year. Credit: ESA

The International Space University’s Space Studies Program will officially open today at ESA in the Netherlands. The nine-week programme will see more than 130 participants representing 37 nationalities take part in lectures, workshops and team projects to gain an interdisciplinary understanding of all aspects of the space industry.

This year’s ISU programme is co-hosted by the Technical University Delft and the Netherlands Space Office, in close cooperation with ESA and Leiden University.

Two groups of participants will focus in particular on issues of space safety and sustainability as they prepare project reports on the role space should play in human adaptation to global climate change and on new ideas for the removal of space debris from Earth orbit using ecologically sound technology.

Looking ahead to sustainable innovation

Omar Hatamleh Credit: ISU/NitzanZohar

“Working with young professionals reminds us all of the need to keep space sustainable for the generations to come,” says Omar Hatamleh, ISU’s Director of the Space Studies Program. “We look ahead to a future of great innovation and technology, but we also realise the importance of making those great advances available to everyone and to make them sustainable over the long term.”

The space debris project will examine some of the proposals by space agencies and commercial companies that include the deorbiting of defunct satellites, moving them to safer orbits or salvaging them for reuse on other satellites or spacecraft, before composing a plan for an original mission. The participants at ISU come from a wide range of backgrounds and experiences and will be encouraged to bring new approaches to the problem.

Rüdiger Jehn Credit: ESA/Euronews

“I’m looking forward to seeing exciting new ideas from the participants in the project,” says team project co-chair Rüdiger Jehn, who is also Co-Manager for Near-Earth Objects within ESA’s Space Situational Awareness Programme.

“We need to guarantee the long-term safety and security of space operations, so that all of the generations to come can benefit from knowledge we gain from space data. Developing awareness of the issue and good ideas for addressing it is really important for everyone with an interest in space.”

Looking at key risks of climate change

The host nation of the Netherlands has a particular interest in another of the team projects, as it looks at two key risks of climate change – flooding and diminished air quality. Lying at or below sea level, the Dutch interest in flood mitigation is clear, while scientists from the Netherlands were also key in developing the Tropomi instrument measuring air quality on board the Sentinel 5P satellite launched last year.

“We welcome participants from many countries to their summer of space in the Netherlands this year,” says Erik Laan, co-chair of the team project on adaptation from space for climate change. “We are interested in understanding how climate change affects different environments and ecosystems, and how our knowledge from space can help us all to minimise the impacts of a changing climate for people on the ground. This international group will allow us to explore new ideas for what will be our common future.”

The opening ceremony of the Space Studies Program will be attended by HM the King of the Netherlands and addressed by ESA Director General Jan Wörner. The ceremony is available to view on ISU’s YouTube channel.

Today’s post contributed by Ruth McAvinia. Ruth is an ATG-Europe editor for ESA and a member of the global faculty of ISU.

More info

ISU SSP in Facebook

Tweets by ISU_SSP

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A special youth and space panel will be held at UNISPACE+50 in Vienna on 19 June, including astronaut Scott Kelly, the UN’s ‘Champion for Space’. The panel will provide a forum to discuss technical advancements and findings in space and new opportunities for society, focussing, as the title implies, on young people!

We asked several young Europeans (and a Canadian!) working at ESA for their perspective on the future and what they hope to see in coming years.

Aybike Demirsan
Hometown: Frankfurt am Main, Germany
Work: Young Graduate Trainee at ESA working on software for the Cluster mission 

Aybike Demirsan

Two years ago, I entered ESA’s Young Graduate Trainee programme with a position at the Agency’s ESOC mission control centre in Darmstadt, Germany. I am working on the Cluster mission, comprising four structurally identical spacecraft that fly in formation to measure the solar wind’s effects on Earth’s magnetosphere.

My job, thanks to my background in computer science, is to reengineer the mission’s monitoring tool, so that it would be easier for the flight control team to monitor the upcoming contacts between our spacecraft and the ground stations. The tool employs a simple visual timeline, with many more functionalities than before, to make our lives as spacecraft operations engineers and spacecraft controllers easier.

I also received training on every subsystem of the spacecraft and learned how to operate spacecraft and how to deal with anomalies, which has been a great journey.

However, it’s not only what we do that fascinates me, but also the way we do it. Never before have I worked with such a diverse crowd of people, and as well I have never before worked in such a peaceful, nourishing environment where knowledge is shared, help is always offered and there is belief and trust in others and yourself to do your job with your best effort. For space in the future, I think youth today can look forward to worldwide collaboration and to overcoming artificial human-created borders!

Artur Scholz
Hometown: Erlangen, Germany
Work: Spacecraft Operations Engineer at ESA working on the Cluster and JUICE missions 

Artur Scholz

For space in future, youth today should most look forward to work together openly, with a focus on sharing and collaboration.

The spirit of open source, which comes from the software world, should be applied to all areas of space exploration – because what we need to truly advance access to space is to allow everyone to get involved!

Dr Francesca Letizia
Hometown: Cagliari, Italy
Work: Space Debris Engineer at ESA working on assessing compliance with space debris mitigation guidelines

Francesca Letizia

There are three main aspects of future space activities that I find exciting. The first one is related to exploration: In the upcoming years, we will witness increasing efforts to send astronauts to Mars and, in general, beyond low Earth orbit. Several projects – like the Lunar Orbiing Platform – Gateway and Moon Village – are evaluating extended human presence in orbits much more distant from Earth than the current International Space Station. These initiatives could contribute to a deeper understanding of the limits of the human body (and mind) in space and how to handle these.

Another interesting field is the development of planet-hunter missions, such as NASA’s Kepler spacecraft now in orbit and the planned ESA Plato and Cheops missions. The goal of these spacecraft is to find planets outside our Solar System and, in particular, to identify planets with a habitable environment. The findings of these missions are incredibly fascinating as they shed light on where life could have developed outside of Earth.

Finally, in the future, space will be more and more an enabler of new technology and applications. This is already happening right now with navigation services such as GPS and could be even more exploited and integrated thanks to the improved accuracy offered by Galileo. Other opportunities are offered by the processing of satellite images in fields such as agriculture or monitoring of land and water use.

Adam Vigneron
Hometown: Wilcox, Saskatchewan, Canada
Work: Navigation Engineer, on contract from Telespazio VEGA Deutschland, at ESA’s Navigation Support Office

Adam Vigneron Credit: J. Martin

My work in the Navigation Support Office has given me a profound example of the way in which space technology is an integral part of our everyday life. The work I do now inspires me to dream of a future where the line between space and daily life continues to blur…

For fifty years, uncrewed spaceflight has been a one-way trip. Two related mission families, active debris removal (ADR) and on-orbit servicing (OOS), are looking to turn this trip on its head. Briefly, ADR involves the removal of dead satellites from useful orbits, while OOS includes the refuelling and repairing of satellites already in orbit.

After numerous stops and starts, rumblings are happening in all the right places. Technology demonstrations of advanced robotics are ongoing on the International Space Station, proving technologies for fuel transfer and battery replacement. It looks as though the world’s first ADR mission, e.Deorbit, will gain attention at next year’s ESA Ministerial Council. Discussions continue at UNCOPUOS, the UN body which allows countries to agree on standards and norms for the peaceful use of outer space. Industrial players around the world are jockeying for position as this market emerges. All the while, valuable orbits in LEO and GEO are slowly but steadily filling up with active satellites and debris alike.

ADR/OOS promise an economically viable revolution in space activities to which today’s globally-minded, engaged youth are well-suited. There is a lot of work to be done, but with determination, we can make these missions come to life and change the way we look at space itself by making in-space repair as everyday ordinary as satellite navigation is today.

Editor’s note

Find out more about the misisons and activities mentioned above:

Cluster mission operations

JUICE mission

Space Debris Office

Navigation Support Office

e.Deorbit/Active debris removal

On-orbit servicing

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Guest post by Ersilia Vaudo Scarpetta

Ersilia Vaudo Scarpetta has been working at the European Space Agency since 1991 and she is currently Chief Diversity Officer.

Ersilia Vaudo | Credits: Zoe Vincent/Wired Italy

Today at Unispace+50, the role of women in space has been placed front and centre, and rightly so.

The topic of diversity and inclusiveness (D&I) has been recently placed high on ESA’s corporate agenda. Through this initiative, ESA intends to enhance its wealth of diversity, and at the same time ensure that the values and the objectives pursued through D&I actions become an inherent feature of the Agency’s policies and business practices.

Last September, as part of this effort, ESA’s commitment toward diversity and inclusiveness was made visible, reinforced and underlined in a policy statement that you can read on ESA’s website. The Agency’s final aim is to create and ensure a modern, inclusive working environment where people value diversity in teams, take others’ perspectives into account and feel comfortable being themselves – regardless of gender, gender identity and expression, age or working experience, sexual orientation, physical or mental challenges, ethnicity or educational, religious or social background.

Actually, diversity is already a distinctive feature of ESA and is one of its greatest assets – same as for its international character. People from 22 European member states (plus Canada and Slovenia as Cooperating State and Associate State, respectively) – speaking more than 18 different languages – work together, discussing and solving problems every day by combining their different cultural backgrounds. It is that richness of diversity, in competences, skills and points of view that allows us to achieve results that could be impossible to reach on the effort of single nations. The Agency has put a renewed effort into striving to enhance the innovative perspectives brought in by a diverse and gender-balanced pool of talent.

Among the different activities undertaken to foster diversity and inclusiveness at ESA, a special focus has been put in ensuring that space jobs are increasingly attractive to women in ESA member states.

In fact, we observe that, although space is recognised as one of the most inspirational sectors in science and technology in Europe, and the number of girls in science, technology, engineering and maths (STEM) is growing in member states, applications from women to ESA are are only holding steady. In addition, if the situation in Europe is improving in terms of girls graduating in STEM fields, this is still a ‘boys’ club’.

Furthermore, in terms of perspectives, we see that the number of women decreases along the different steps of a STEM career. It becomes therefore clear that we need to challenge stereotypes, become more proactive in promoting space jobs and work for the right conditions for retaining and ensuring career perspectives to women.

ESA is part of a number of external networks with other international organisations to promote discussions on these issues, exchanging ideas as well on current measures and best practices. It is with this aim that ESA has established a network with member states on diversity and inclusiveness, is part of the ad-hoc EIROforum Working Group on Diversity, and has initiated a collaboration with the OECD on the topic of gender and stereotypes in science. ESA is also corporate member of Women in Aerospace Europe.

Ersilia Vaudo | Credits: Zoe Vincent/Wired Italy

With the Agency facing a significant retirement wave coming over the next 10-15 years, this moment really represents the perfect occasion to project the ‘ESA of the future’ and to start injecting more diversity into the workforce.

ESA already has a long-standing commitment to promoting gender diversity and equal opportunities. Focusing on, and strongly committing to, the involvement of women in STEM is more important today than ever in order to continue and expand ESA’s enduring value – and enhance it in the future from a Space 4.0 perspective. In fact, in the next decades we will be more and more in need of a creative and diverse pool of talent to address challenges of the future.

With this overarching objective in mind, the Agency is now working to achieve measurable goals in terms of female recruitment and representation. For example, in terms of new recruitments we will be aiming at a minimum 30% of new positions filled by women by 2019. In addition, efforts have been put in place to increase the proportion of women in leadership positions, which is at ESA around 10%.

Furthermore, since the Agency receives a gender-balanced number of applications at the young-graduate level while the number of women interested in permanent jobs drops to about 20%, ESA is opening the early-career scheme also to people in their 30s with some years of working experience.

Finally, the Chief Diversity Officer and many of ESA’s female professionals regularly engage in branding and outreach activities to inspire girls and young women across Europe to enter STEM disciplines, encouraging in particular careers in science, engineering and space.

Indeed, at ESA we are sure that diversity will help us strengthen innovation, lessen resistance to change, obtain a broader understanding of societal needs, boost motivation, inspire people and foster knowledge sharing. Spurred on by the UN’s Sustainable Development Goals (SDGs), and in particular SDGs that aims at equal opportunities for all women and girls, ESA has a major objective to inspire the young generation of girls to enter the STEM field and in particular to attract more women to the wealth of careers and jobs that space can offer.

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A tired but very happy Mars Express flight control team pulled shift through the night between 16 and 17 April, overseeing the successful reboot and recovery of ESA’s nearly 15-year-old Red Planet explorer following the installation of significant updates to the spacecraft’s operating system.

One online media channel, following the event via Twitter, reported: “The team behind the European Space Agency’s Mars Express were cock-a-hoop with delight last night after hitting the big red button to restart and install updates on the veteran orbiter.”

It’s true. We were!

Just like when your smartphone or tablet receives new software to improve its functionality and extend its life, Mars Express got an upgrade to enable it to keep flying despite the fact that several critical components (ring-laser gyros) are wearing out (see Mars Express V2.0 for details).

But unlike with your phone or tablet, this update was delivered across 144.6 million km of space.

There was a bit of tension in the Interplanetary Control Room at ESOC last night, especially between sending the reboot command at 19:15 CEST and waiting for the craft to restart and send a signal about an hour later.

Spacecraft operations engineers are naturally risk averse and prone to pessimism, and – rightly so – they hate just hanging around waiting for a possibly recalcitrant spacecraft to do what it’s been told.

But, if you followed @esaoperations via Twitter, you’ll know the expected signal came in around 20:15 CEST and the initial results were entirely good, which is to say, entirely as expected:

Receipt of the low-bitrate signal from #MarsExprsss is great news! This means the craft has rebooted. Now waiting for telemetry – onboard status info… #rday

— ESA Operations (@esaoperations) April 16, 2018

That happy feeling when your phone restarts! Initial #MarsExpress status looks good! It is running on the new software & its systems appear to be operating as expected #Rday

— ESA Operations (@esaoperations) April 16, 2018

The update from the team today confirms their initial reaction: the spacecraft is doing well and the newly updated software is working more or less as expected.

“Everything went according to plan with only minor issues,” says Spacecraft Operations Manager James Godfrey.

“Today, the team on shift is concentrating on reconfiguring the spacecraft into normal operating mode, testing functionalities and checking to see if anything fails to work with the new software.”

This testing and shakeout will continue for the next approximately 7 to 8 days, and the team expect to be able to switch the science instruments back on and return to routine observations by the end of April.

“Everyone at ESA did an excellent job in this entire upgrade effort,” says ESA Flight Director Michel Denis.

“It took a lot of work and coordination by the flight controllers, assisted by experts from flight dynamics, ground stations and software support as well as by our colleagues working on the Mars Express Science Operations team.”

“We have a spacecraft in excellent shape and promising many more years of exploration at Mars.”

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Editor’s note: ESA’s Space Debris team have sent in a final update on the reentry of Tiangong-1.

As we posted earlier, around once a year, ESA takes part in a joint tracking campaign run by the Inter Agency Space Debris Coordination Committee (IADC), which consists of experts from 13 space organisations such as NASA, Roscosmos, CNSA and European and other national agencies.

With the agreement of all members, Tiangong-1’s reentry was the mission selected for this year’s campaign.

During the now-completed campaign, participants pooled their predictions of the time window, as well as their respective tracking datasets obtained from radar and other sources, with the aim of cross-verifying, cross-analysing and improving the prediction accuracy for all members.

ESA has been acting as host and administrator for the campaign, as it has done for the about twenty previous IADC test campaigns since 1998.

Tiangong-1 seen at an altitude of about 161 km by the powerful TIRA research radar operated by the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR) near Bonn, Germany. Image acquired on the morning of 1 April 2018, during one of the craft’s final orbits. Credit: Fraunhofer FHR

Besides the IADC campaign, ESA also had an operational role: Throughout the past days it supplied its own predictions to national alert and civil protection centres of Member States.

Confirmation of this morning’s Tinagong-1 reentry was published by the US military, who issued a press release today at around 04:00 CEST.

They stated that reentry had occurred over the southern Pacific Ocean at approximately 5:16 p.m. (PST), which was 02:16 CEST – this was well within ESA’s earlier reentry forecast window, which ran from 23:00 UTC on 1 April to 03:00 UTC on 2 April (01:00 CEST to 05:00 CEST on 2 April).

“According to our experience, their assessment is very reliable,” says Holger Krag, Head of ESA’s Space Debris Office.

“This corresponds to a geographic latitude of 13.6 degrees South and 164.3 degrees West – near American Samoa in the Pacific, near the international date Line.

“Both time and location are well within ESA’s last prediction window.”

Holger notes that, afterwards, at 04:05 UTC (06:05 CEST), had Tiangong-1 still been in orbit, it would have become visible to the Fraunhofer FHR institute’s TIRA radar, located near Bonn. In fact, the team working at TIRA reported that the spacecraft was no longer visible, giving additional confirmation that it had reentered.

Indeed, data supplied by many a number of ESA partners were crucial to enable the space debris team to conduct their work. “We’d certainly like to thank all our partners who supported ESA throughout this campaign,” says Holger.

China’s CMSA manned space agency also made a public statement.

It’s interesting to note, from a European perspective, how limited our capabilities still are after all. Most of the data on space objects that ESA receives today comes from non-European sources.

Europe’s missing information

Commands for a debris avoidance manoeuvre being sent to ESA’s Swarm-B on 25 January 2017. Credit: ESA

“This illustrates again the dependence that Europe has on non-European sources of information to properly and accurately manage space traffic, detect reentries such as Tiangong-1 and track space debris that remains in orbit – which routinely threatens ESA, European and other national civil, meteorological, scientific, telecomm and navigation satellites,” says Holger.

The US military routinely warns ESA when one of the Agency’s satellites may be at risk for collision with a piece of space debris, an event that is happening with increasing frequency (see Anatomy of a debris incident).

Holger points out that Europe also lacks the means to independently confirm reentries the size of Tiangong-1, which occur almost weekly, by using, for example, an infrared tracking payload mounted on a geostationary satellite.

Space weather, too

He also mentions that, three days ago, solar-generated space weather gave us a surprise, when the Sun’s activity spontaneously dropped compared to what the team expected.

“This delayed the Tiangong-1 reentry by about half a day.”

Concept for ESA’s future space weather monitoring mission at the Sun. Credit: ESA/A. Baker, CC BY-SA 3.0 IGO

Earlier this year, ESA in cooperation with European industry began a multi-year study to examine a new mission (see “Where no mission has gone before“) that would continuously observe our Sun and provide crucial data that will help us improve our forecasts of solar activity and its effects on spacecraft, satellites in orbit and critical infrastructure on ground such as power grids and oil pipelines.

Since 2009, ESA has been developing software, technologies and precursor systems to test a fully European network of radars, telescopes and other detectors that would provide independent data on the risks from spaceflight.

Concept for ESA’s future space debris surveillance system employing ground-based optical, radar and laser technology as well as in-orbit survey instruments. Credit: ESA/Alan Baker, CC BY-SA 3.0 IGO

“Today, everyone in Europe relies on the US military for space debris orbit data – we lack the radar network and other detectors needed to perform independent tracking and monitoring of objects in space,” says Holger.

“This is needed to allow meaningful European participation in the global efforts for space safety.”

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The US air force has confirmed the reentry of the Tiangong-1 spacecraft at about 02:16 CEST this morning over the southern Pacific Ocean. The location of the reentry was, by chance, not too far from the so-called South Pacific Ocean Unpopulated Area. The SPOUA has long been used by many space agencies including ESA, to dispose of end-of-life spacecraft through controlled reentries. 

The air force wrote:

The JFSCC used the Space Surveillance Network sensors and their orbital analysis system to confirm Tiangong-1’s reentry, and to refine its prediction and ultimately provide more fidelity as the reentry time approached. This information is publicly-available on USSTRATCOM’s website www.Space-Track.org. The JFSCC also confirmed reentry through coordination with counterparts in Australia, Canada, France, Germany, Italy, Japan, South Korea, and the United Kingdom.

JFSCC tracks Tiangong-1’s reentry over the Pacific Ocean

VANDENBERG AIR FORCE BASE, Calif. — U.S. Strategic Command’s (USSTRATCOM) Joint Force Space Component Command (JFSCC), through the Joint Space Operations Center (JSpOC), confirmed Tiangong-1 reentered the Earth’s atmosphere over the southern Pacific Ocean at approximately 5:16 p.m. (PST) April 1, 2018.


 

Read full report via:

http://www.vandenberg.af.mil/News/Article-Display/Article/1481734/jfscc-tracks-tiangong-1s-reentry-over-the-pacific-ocean/

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Main Control Room at ESA’s European Space Operations Centre, Darmstadt, Germany. Credit: ESA/P. Shlyaev

With the reentry of Tiangong-1 now forecast to happen within a few hours, ESA’s formal role in the tracking campaign is winding down.

To recall, here’s what’s been happening.

Each year, about 100 tonnes of defunct satellites, uncontrolled spacecraft, spent upper stages and discarded items like instrument covers are dragged down by Earth’s upper atmosphere, ending their lives in flaming arcs across the sky.

While still in orbit, these and many other objects are tracked by a US military radar network, which shares the data with ESA, since Europe has no such capability of its own.

IADC campaign

Around once a year, ESA takes part in a joint tracking campaign run by the Inter Agency Space Debris Coordination Committee, which consists of experts from 13 space organisations such as NASA, Roscosmos, CNSA and European and other national agencies.

With the agreement of all members, Tiangong-1’s reentry was the mission selected for this year’s campaign.

During the campaign, participants have been pooling their predictions of the time window, as well as their respective tracking datasets obtained from radar and other sources, with the aim of cross-verifying, cross-analysing and improving the prediction accuracy for all members.

ESA has been acting as host and administrator for the campaign, as it has done for the twenty previous IADC test campaigns since 1998. A special case for ESA was the campaign in 2013 during the uncontrolled reentry of ESA’s own GOCE satellite.

The China Manned Spaceflight organisation have been providing their own updates on reentry, and additional Tiangong-1 orbit information is here.

ESA’s reentry expertise

In addition to IADC campaigns, it is the task of ESA’s Space Debris team to generate its own independent predictions to ESA Member States and partner civil authorities around the globe.

ESA reentry expertise - YouTube

The team mix in additional tracking information gleaned from European sources, such as Germany’s Fraunhofer research radar near Bonn or telescopes and other detectors run by a mix of institutional and private researchers, to generate reentry forecasts – a challenging and imprecise art.

We’ve been posting ESA’s reentry forecasts regularly here in the blog, and sharing the link via social media.

Getting close

In just a few hours, we’ll be well within the uncertainty window associated with this reentry, and we don’t expect any more forecast updates with any higher accuracy. In other words, we’re at the limit of what we can forecast.

Just over an hour ago, ESA’s space debris team provided their final estimate for reentry, forecasting a window of about four hours between 23:00 UTC on 1 April to 03:00 UTC on 2 April (01:00 CEST on 2 April to 05:00 CEST on 2 April).

Final Tiangong-1 reentry window forecast for 18:00 CEST 1 April Credit: ESA

Final Tiangong-1 altitude decay forecast as of 18:00 CEST, 1 April Credit: ESA

“With our current understanding of the dynamics of the upper atmosphere and Europe’s limited sensors, we are not able to make very precise predictions,” says Holger Krag, head of ESA’s Space Debris Office.

Holger says that there will always be an uncertainty of a few hours in all predictions, and that even just a day or so before any reentry, like now, the uncertainty window can be very large.

“The high speeds of returning satellites mean they can travel thousands of kilometres during that time window, and that makes it very hard to predict a precise location of reentry.”

Spotting reentry

It is likely that the pending reentry of Tiangong-1 will occur over water, probably unseen by anyone (although possibly detected by radar or other sensors).

Tiangong-1 seen at an altitude of about 161 km by the powerful TIRA research radar operated by the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR) near Bonn, Germany. Image acquired on the morning of 1 April 2018, during one of the craft’s final orbits. Credit: Fraunhofer FHR

Our planet is a big place, mostly covered by water, and if any pieces survive the fiery reentry, these are unlikely to be found by anyone, sinking instead to the bottom of some ocean, or landing far from human habitation.

If you do witness the event, we’d certainly like to see any images you get.

These will help ESA’s debris team conduct their post-reentry analysis, and improve models and forecasts for future.

We need the time, your location (GPS coordinates fine) and – ideally – the direction in which you were facing when you saw any arc across the sky.

You can share your photos via Twitter (just tag @esaoperations), or mail them to esoc.communication@esa.int. We’ll reply for a confirmation and any follow-up.

In the unlikely case that you find a piece of debris on ground, leave it alone and inform your local authorities.

Our final word comes from last week’s web article, which closed with an observation worth repeating:

Since 2009, ESA has been developing software, technologies and precursor systems to test a fully European network that would provide independent data on the risks from spaceflight.

“Today, everyone in Europe relies on the US military for space debris orbit data – we lack the radar network and other detectors needed to perform independent tracking and monitoring of objects in space,” says Holger Krag.

“This is needed to allow meaningful European participation in the global efforts for space safety.”

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Every week, on average, a substantial, inert satellite drops into our atmosphere and burns up. Monitoring these reentries and warning European civil authorities has become routine work for ESA’s space debris experts.

ESA reentry expertise - YouTube

Each year, about 100 tonnes of defunct satellites, uncontrolled spacecraft, spent upper stages and discarded items like instrument covers are dragged down by Earth’s upper atmosphere, ending their lives in flaming arcs across the sky.

Some of these objects are big and chunky, and pieces of them survive the fiery reentry to reach the surface. Our planet, however, is a big place, mostly covered by water, and much of what falls down is never seen by anyone, sinking to the bottom of some ocean, or landing far from human habitation.

While still in orbit, these and many other objects are tracked by a US military radar network, which shares the data with ESA, since Europe has no such capability of its own.It’s the task of ESA’s Space Debris team to look at these data and issue updates to ESA Member States and partner civil authorities around the globe.

Access full text via ESA web.

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